Spiral timepiece spring
US-2018373202-A1 · Dec 27, 2018 · US
for springs
for springs · Cooperative Patent Classification (CPC)
Chemical and metallurgical processes, compounds, and materials.
Related technology areas
Mapped technology topics for this CPC code.
| Metric | Value |
|---|---|
| CPC code | C21D9/02 |
| Official title | for springs |
| Display label | for springs |
| Total patents | 159 |
Filing trend
Year-over-year patent counts classified under this CPC code.
Filing activity over the last five years is declining.
| Year | Patents |
|---|---|
| 2015 | 16 |
| 2016 | 14 |
| 2017 | 25 |
| 2018 | 15 |
| 2019 | 18 |
| 2020 | 19 |
| 2021 | 11 |
| 2022 | 7 |
| 2023 | 10 |
| 2024 | 14 |
| 2025 | 8 |
| 2026 | 2 |
Representative patents
Representative publications under this CPC code from precomputed stats, or recent filings when stats are unavailable.
High strength spring steel and steel wire
US-10131973-B2 · Nov 20, 2018 · US
Hollow seamless steel pipe for spring
US-2018265952-A1 · Sep 20, 2018 · US
Spring steel
US-2018142333-A1 · May 24, 2018 · US
Carburization device and carburization method
US-2018080113-A1 · Mar 22, 2018 · US
Stabilizer
US-2017349962-A1 · Dec 7, 2017 · US
Production method for stabilizers
US-2017349961-A1 · Dec 7, 2017 · US
Leaf spring device and method for manufacturing leaf spring device
US-2017313149-A1 · Nov 2, 2017 · US
Method for manufacturing steel for high-strength hollow spring
US-2017306432-A1 · Oct 26, 2017 · US
High strength spring steel having excellent corrosion resistance
US-2017298486-A1 · Oct 19, 2017 · US
Method for producing cold-formed steel springs
US-2017283904-A1 · Oct 5, 2017 · US
Method for producing hot-formed steel springs
US-2017275721-A1 · Sep 28, 2017 · US
Helical compression spring and method for manufacturing same
US-9752636-B2 · Sep 5, 2017 · US
Stainless steel spring and stainless steel spring manufacturing method
US-2017233844-A1 · Aug 17, 2017 · US
Si-killed steel wire rod and spring
US-9725779-B2 · Aug 8, 2017 · US
Leaf spring and method of manufacture thereof having sections with different levels of through hardness
US-2017204488-A1 · Jul 20, 2017 · US
Hollow seamless pipe for high-strength springs
US-9689051-B2 · Jun 27, 2017 · US
Ultra high-strength spring steel
US-2017159160-A1 · Jun 8, 2017 · US
Ultra-high-strength spring steel for valve spring
US-2017159161-A1 · Jun 8, 2017 · US
Method for improving an iron-nickel-chromium-manganese alloy for timepiece applications
US-2017159144-A1 · Jun 8, 2017 · US
Frequently asked questions
Answers are generated from the same data shown on this page.
- What is CPC C21D9/02?
- CPC C21D9/02 is the Cooperative Patent Classification code for “for springs.”
- How many patents are filed under CPC C21D9/02 (for springs)?
- Our database includes 159 publications tagged with this CPC code.
- Is patent activity under CPC C21D9/02 growing?
- Publication counts under this code: 14 in 2024 vs 8 in 2025 (latest complete years).